U.S. patent application number 15/027792 was filed with the patent office on 2016-08-11 for optical coupling and assembly.
This patent application is currently assigned to Molex, LLC. The applicant listed for this patent is Roger KOUMANS, MOLEX INCORPORATED, Russell K. STILES, David W. WHITNEY. Invention is credited to Roger KOUMANS, Russell K. STILES, David W. WHITNEY.
Application Number | 20160231518 15/027792 |
Document ID | / |
Family ID | 52828603 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160231518 |
Kind Code |
A1 |
STILES; Russell K. ; et
al. |
August 11, 2016 |
OPTICAL COUPLING AND ASSEMBLY
Abstract
An optical interconnect assembly includes an optical coupling
component having a body formed of a polymer material. The body has
a reflecting surface defining a first focal point and a second
focal point, a first focal surface generally aligned with the first
focal point, and a second focal surface generally aligned with the
second focal point. The first focal surface and the second focal
surface are spaced apart and at an angle to each other, and an
optical path extends through the body from the first focal point to
the reflecting surface and to the second focal point. An optical
source from which a light signal is transmitted is positioned
adjacent the first focal surface and an optical target at which the
light signal is received is positioned adjacent the second focal
surface.
Inventors: |
STILES; Russell K.; (Downers
Grove, IL) ; KOUMANS; Roger; (Irvine, CA) ;
WHITNEY; David W.; (Santa Rosa, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STILES; Russell K.
KOUMANS; Roger
WHITNEY; David W.
MOLEX INCORPORATED |
Lisle
Lisle
Lisle
Lisle |
IL
IL
IL
IL |
US
US
US
US |
|
|
Assignee: |
Molex, LLC
Lisle
IL
|
Family ID: |
52828603 |
Appl. No.: |
15/027792 |
Filed: |
October 14, 2014 |
PCT Filed: |
October 14, 2014 |
PCT NO: |
PCT/US2014/060434 |
371 Date: |
April 7, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61890541 |
Oct 14, 2013 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/4212 20130101;
G02B 6/4255 20130101; G02B 6/4206 20130101; G02B 6/262 20130101;
G02B 6/4214 20130101 |
International
Class: |
G02B 6/42 20060101
G02B006/42; G02B 6/26 20060101 G02B006/26 |
Claims
1. An optical interconnect assembly, the optical interconnect
assembly comprising: an optical coupling component having a body
formed of a polymer material, the body having an ellipsoidal
reflecting surface defining a first focal point and a second focal
point, a first focal surface generally aligned with the first focal
point, a second focal surface generally aligned with the second
focal point, the first focal surface and the second focal surface
being spaced apart and at an angle to each other, and an optical
path extending through the body from the first focal point to the
reflecting surface and to the second focal point; an optical source
from which a light signal is transmitted, the optical source being
positioned adjacent the first focal surface; and an optical target
at which the light signal is received, the optical target being
positioned adjacent the second focal surface.
2. The optical interconnect assembly of claim 1, wherein the angle
of the first focal surface relative to the second focal surface is
between approximately 70 and 110 degrees.
3. The optical interconnect assembly of claim 1, wherein the angle
of the first focal surface relative to the second focal surface is
approximately 90 degrees.
4. The optical interconnect assembly of claim 1, wherein the
optical source is positioned relative to the first focal surface so
that an optical signal enters the optical coupling component at the
first focal surface generally perpendicular to the first focal
surface and the optical target is positioned relative to the second
focal surface so that an optical signal exits the optical coupling
component at the second focal surface generally perpendicular to
the second focal surface.
5. The optical interconnect assembly of claim 1, wherein at least
one of the optical source and the optical target is a single mode
optical fiber.
6. The optical interconnect assembly of claim 1, wherein the
optical source is an emitter.
7. The optical interconnect assembly of claim 1, wherein the
optical target is a detector.
8. The optical interconnect assembly of claim 1, wherein a first
gap exists between the optical source and the first focal surface,
a second gap exists between the optical target and the second focal
surface, and an index matched medium is positioned within each
gap.
9. The optical interconnect assembly of claim 8, wherein the
optical coupling component has a refractive index of about 1.56 and
the index matched medium has a refractive index of about 1.52.
10. The optical interconnect assembly of claim 8, wherein the index
matched medium fills each gap.
11. The optical interconnect assembly of claim 1, wherein the
entire optical path s through the polymer material.
12. The optical interconnect assembly of claim 1, wherein an outer
surface of the body adjacent the reflecting surface has a
reflective coating thereon.
13. The optical interconnect assembly of claim 12, wherein the
reflective coating is chosen from one of gold, silver and a gold
alloy.
14. The optical interconnect assembly of claim 1, wherein the first
focal surface intersects with the first focal, point and the second
focal surface intersects with the second focal point.
15. An optical coupling component for optically coupling a first
optical component to a second optical component, comprising: a body
formed of a polymer material, the body having: an ellipsoidal
reflecting surface defining a first focal point and a second focal
point, a first focal surface aligned with the first focal point; a
second focal surface aligned with the second focal point, the first
focal surface and the second focal surface being spaced apart and
at an angle to each other; and an optical path extending through
the body from the first focal point to the reflecting surface and
to the second focal point.
6. The optical coupling component of claim 15, wherein the entire
optical path is through the polymer material.
17. The optical coupling component of claim 15, wherein an outer
surface of the body adjacent the reflecting surface has a
reflective coating thereon.
18. The optical coupling component of claim 7, wherein the
reflective coating is chosen from one of gold, silver, and a gold
alloy.
19. The optical coupling component of claim 15, wherein the first
fiscal surface intersects with the first focal point and the second
focal surface intersects with the second focal point.
20. An optical interconnect assembly comprising: an optical
coupling component having a body formed of a polymer material, the
body having a reflecting surface defining a first focal point and a
second focal point, a first focal surface generally aligned with
the first focal point, a second focal surface generally aligned
with the second focal point, the first focal surface and the second
focal surface being spaced apart and at an angle to each other, and
an optical path extending through the body from the first focal
point to the reflecting surface and to the second focal point; an
optical source, the optical source being positioned adjacent the
first focal surface; and an optical target, the optical target
being positioned adjacent the second focal surface.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The Present Disclosure claims priority to prior-filed U.S.
Provisional Patent Application No. 61/890,541, entitled "Athermal
Optical Geometry For Fiber Coupling," filed on 14 Oct. 2013 with
the United States Patent And Trademark Office. The content of the
aforementioned Patent Application is incorporated in its entirety
herein.
BACKGROUND OF THE PRESENT DISCLOSURE
[0002] The Present Disclosure relates generally to optical
assemblies and, more particularly, to an optical coupling component
and assembly in which changes in temperature have a reduced
operational impact.
[0003] A significant issue when using polymer optics is the
performance of the optical system over temperature. For example,
optic components made from polymers have fundamental properties
inherent to the material, such as, changes in Refractive Index with
temperature (dN/dT) and coefficients of thermal expansion (CTE),
that are typically ten times larger than glass or electronic
substrates and glass filled polymers to which they are attached.
These fundamental properties limit the use of polymer optical
components in many fiber optic connection applications.
[0004] In some applications, the large dN/dT and CTE properties may
generate a change in focused light position that results in a
degradation of performance of the optical connection over
temperature. This degradation of performance limits and sometimes
prevents the use of polymer optic components in many fiber optic
applications. In some instances, single mode fiber optic
applications may be especially susceptible to degradation of
performance due to the effects of changes in temperature.
[0005] The foregoing background discussion is intended solely to
aid the reader. It is not intended to limit the innovations
described herein, nor to limit or expand the prior art discussed.
Thus, the foregoing discussion should not be taken to indicate that
any particular element of a prior system is unsuitable for use with
the innovations described herein, nor is it intended to indicate
that any element is essential in implementing the innovations
described herein. The implementations and application of the
innovations described herein are defined by the appended
claims.
SUMMARY OF THE PRESENT DISCLOSURE
[0006] In one aspect, an optical interconnect assembly includes an
optical coupling component having a body formed of a polymer
material. The body has an ellipsoidal reflecting surface defining a
first focal point and a second focal point, a first focal surface
generally aligned with the first focal point, and a second focal
surface generally aligned with the second focal point. The first
focal surface and the second focal surface are spaced apart and at
an angle to each other, and an optical path extends through the
body from the first focal point to the reflecting surface and to
the second focal point. An optical source from which a light signal
is transmitted is positioned adjacent the first focal surface and
an optical target at which the light signal is received is
positioned adjacent the second focal surface.
[0007] In another aspect, an optical coupling component for
optically coupling a first optical component to a second optical
component includes a body formed of a polymer material. The body
has an ellipsoidal reflecting surface defining a first focal point
and a second focal point, a first focal surface aligned with the
first focal point and a second focal surface aligned with the
second focal point. The first focal surface and the second focal
surface are spaced apart and at an angle to each other and an
optical path extends through the body from the first focal point to
the reflecting surface and to the second focal point.
[0008] In still another aspect, an optical interconnect assembly
includes an optical coupling component having a body formed of a
polymer material. The body has a reflecting surface defining a
first focal point and a second focal point, a first focal surface
generally aligned with the first focal point, and a second focal
surface generally aligned with the second focal point. The first
focal surface and the second focal surface are spaced apart and at
an angle to each other and an optical path extends through the body
from the first focal point to the reflecting surface and to the
second focal point. An optical source is positioned adjacent the
first focal surface and an optical target is positioned adjacent
the second focal surface.
BRIEF DESCRIPTION OF THE FIGURES
[0009] The organization and manner of the structure and operation
of the Present Disclosure, together with further objects and
advantages thereof, may best be understood by reference to the
following Detailed Description, taken in connection with the
accompanying Figures, wherein like reference numerals identify like
elements, and in which:
[0010] FIG. 1 is a schematic illustration of an optical coupling
system according to the disclosure;
[0011] FIG. 2 is a perspective view of an optical coupling system
according to the disclosure;
[0012] FIG. 3 is a perspective view similar to FIG. 2 but taken
from a different perspective;
[0013] FIG. 4 is a section of the optical coupling system taken
generally along line 4-4 in FIG. 2;
[0014] FIG. 5 is a perspective view of an alternate embodiment of
an optical coupling system with optical fibers coupled to the
coupling component;
[0015] FIG. 6 is a perspective view of another alternate embodiment
of an optical coupling system with an emitter and a detector
coupled to the coupling component; and
[0016] FIG. 7 is a schematic illustration of an alternate
embodiment of the coupling component of the optical coupling
system.
DETAILED DESCRIPTION
[0017] While the Present Disclosure may be susceptible to
embodiment in different forms, there is shown in the Figures, and
will be described herein in detail, specific embodiments, with the
understanding that the Present Disclosure is to be considered an
exemplification of the principles of the Present Disclosure, and is
not intended to limit the Present Disclosure to that as
illustrated.
[0018] As such, references to a feature or aspect are intended to
describe a feature or aspect of an example of the Present
Disclosure, not to imply that every embodiment thereof must have
the described feature or aspect. Furthermore, it should be noted
that the description illustrates a number of features. While
certain features have been combined together to illustrate
potential system designs, those features may also be used in other
combinations not expressly disclosed. Thus, the depicted
combinations are not intended to be limiting, unless otherwise
noted.
[0019] In the embodiments illustrated in the Figures,
representations of directions such as up, down, left, right, front
and rear, forward and rearward, used for explaining the structure
and movement of the various elements of the Present Disclosure, are
not absolute, but relative. These representations are appropriate
when the elements are in the position shown in the Figures. If the
description of the position of the elements changes, however, these
representations are to be changed accordingly.
[0020] FIGS. 1-4 depict an optical coupling system 10 for optically
coupling two components together. As depicted, a first optical
component or optical source 11 and a second optical component or
optical target 12 are optically coupled by a transparent optical
coupling component 20, More specifically, coupling component 20
directs optical signals in the form of light from the first optical
component 11 to the second optical component 12. In one embodiment,
the first optical component 11 may be any optical source such as a
semi-conductor emitter or transmitter or an optical fiber through
which an optical signal is transmitted. The second optical
component 12 may be any optical target such as a semi-conductor
detector or receiver or an optical fiber into which an optical
signal is directed.
[0021] Coupling component 20 may be a one-piece polymer or resin
member that includes a reflecting surface 21 together with a first
focal surface 30 spaced from and opposing the reflecting surface
and a second focal surface 35 that is also spaced from and opposing
the reflecting surface. The first focal surface 30 is spaced from
and at an angle to the second focal surface 35. The angle between
the first focal surface 30 and the second focal surface 35 may be
any desired angle provided that the other characteristics of the
optical component 20 as described below are met, In sonic
applications, the angle between the first focal surface 30 and the
second focal surface may be between approximately 70 and 110
degrees. In other application the angle may be approximately 90
degrees.
[0022] Reflecting surface 21 may have an ellipsoidal shape or
surface (FIGS. 2-3) to create or define a pair of optical foci or
focal points 31, 36, An ellipse defining a portion of the
reflecting surface 21 is depicted in dashed line 38 for clarity.
First focal point 31 may fall on or be aligned with first focal
surface 30 and second focal point 36 may fall on or be aligned with
the second focal surface 30. By aligning the first focal point 31
in three dimensions (x, y and z) with the first optical component
11 and second focal point 36 in three dimensions with the second
optical component 12, losses within the optical coupling between
the first optical component and the second optical component may be
minimized.
[0023] It should be noted that in some instances, it may be
desirable to only generally align the focal surfaces with the
respective foci. For example, this may occur when it is desirable
for the beam of light being transmitted to be focused at a
specified diameter rather than a specified point or in instances in
which exact alignment is not required for system performance. In
such case, the light enters and exits coupling component 20 at a
focal plane rather than a point.
[0024] As depicted in FIG. 1, the major axis 39 of ellipse 38
(i.e., a line through the foci) is at an angle to both the first
focal surface 30 and the second focal surface 35. The angle of the
major axis 39 relative to the focal surfaces coincides with the
angle of the reflecting surface relative to the focal surfaces.
[0025] As depicted in FIG. 1, first focal surface 30 is configured
as a source location aligned with first optical component 11 and
second focal surface 31 is configured as a target location aligned
with second optical component 12. As such, optical signals in the
form of a beam of light may enter the first focal surface 30 at an
angle generally perpendicular to the first focal surface, reflect
off of the reflecting surface 21, and exit from the second focal
surface 35 at an angle generally perpendicular to the second focal
surface. However, the first optical component 11 and the second
optical component 12 may be reversed with the coupling component 20
operating with equal effectiveness.
[0026] In other words, the coupling component 20 operates in an
equally effective manner regardless of whether tight is being
transmitted from the first focal surface 30 to the second focal
surface 35 or if light is being transmitted from the second focal
surface to the first focal surface. As an example, the first
optical component 11 is depicted in FIG. 1 as an optical fiber 13
and second optical component 12 as a detector 14. In FIG. 5, both
the first optical component 11 and the second optical component are
depicted as optical fibers 13. In FIG. 6, the first optical
component 11 is depicted as an emitter 15 and the second optical
component is depicted as a detector 14.
[0027] Optical component 20 may be formed of an optical grade
polymer that is capable of being injection molded, formed as part
of an additive process (e.g., 3-D printed) or otherwise formed,
such as polycarbonate, cyclic olefin or Ultem..RTM. By positioning
optical component 20 so that the reflecting surface 21 is in
contact with air, the differences in the indices of refraction
between the optical component and air causes light to reflect
efficiently off of the reflecting surface. That is, provided that
the light engages the reflecting surface at an angle greater than
the Brewster angle, the ellipsoidal shaped reflecting surface 21
operates as a total internal reflecting mirror that efficiently
reflects light that enters the optical component 20 at the first
focal point 31 and focuses the light at the second focal point 36.
As a result, light entering the optical component 20 from the first
optical component 11 will reflect off of reflecting surface 21 and
direct the light into second optical component 12.
[0028] As depicted in FIGS. 1-6, an optical signal transmitted
through coupling component 20 may be depicted as a beam or a bundle
of rays 50. A first component of the beam is depicted at 51
entering optical component 20 at a first angle generally
perpendicular to first focal surface 30 at source location 30 and
reflects off of reflecting surface 21 at location 22 at a first
reflecting angle 52 so that the light is reflected to second focal
point 36. In addition, a second component of the beam that
represents one outer vertical boundary of the beam is depicted at
53 entering optical component 20 at a second entry angle 54
relative to surface 31 at source location 30 and reflects off of
reflecting surface 21 at location 23 at a second reflecting angle
55 so that the light is reflected to second focal point 36. Still
further, a third component of the beam that represents an opposite
outer vertical boundary of the beam is depicted at 56 entering
optical component 20 at a third entry angle 57 relative to surface
30 at source location 30 and reflects off of reflecting surface 21
at location 24 at a third reflecting angle 58 so that the light is
reflected to second focal point 36. Thus, as the light from first
optical component 11 expands as it enters optical component 20, all
of the light will be reflected to the second focal point 36.
[0029] Referring to FIGS. 2-3 and 5-6, it should be understood that
the beam of light 50 will expand in three dimensions to form a
relative conical shape and the ellipsoidal shape of the reflecting
surface will reflect the light to the second focal point 36. For
example, light enters the coupling component 20 at first focal
surface 30 as a relatively small collimated beam of light 59. The
beam expands in three dimensions as it travels through coupling
component 20 until it reaches reflecting surface 21, The beam of
light will contact the reflecting surface 21 in a generally
elliptical shape as depicted at 60 (FIG. 2) and reflect off of the
reflecting surface.
[0030] The beam of light will taper or focus as depicted at 61
until it reaches the second focal point 36 In a manner similar to
the outer vertical boundaries of the beam that are depicted at 53
and 56 (as depicted in FIG. 1), the lateral or horizontal expansion
of the beam of light will also be redirected by the ellipsoidal
reflecting surface 21 to the second focal point 36. One lateral
outer boundary of the beam of light 50 as it expands is depicted in
FIGS. 2-3 at 62 and a lateral outer boundary as the beam of light
contracts or is focused is depicted at 63.
[0031] Under ideal operating conditions, reflecting surface 21
operates as a total internal reflecting mirror due to the shape of
the surface and the difference in the indices of refraction between
the optical coupling component 20 (optical grade polymer) and the
atmosphere (air) surrounding the reflecting surface. However, if a
contaminant or foreign material (e.g., water, dirt, dust, adhesive)
is in contact with the outer surface 25 of the reflecting surface
21, such undesired material will change the difference in the
indices of refraction between the optical component 20 and the air
at the location of the contaminant and thus change the optical
characteristics of the reflecting surface at the contaminant.
[0032] In order to reduce the risk of such a change in the
reflecting characteristics of the reflecting surface 21, and a
corresponding change in the performance of coupling component 20,
it may be desirable to add or apply a reflective coating or plating
40 (FIG. 7) to the outer surface 25 of the optical component 20
along the reflecting surface 21. The coating 40 provides additional
reflectivity in case any contaminants or foreign materials come
into contact with or become affixed to the outer surface of the
reflecting surface. The reflective coating 40 may be any highly
reflective material such as gold, silver, or any other desired
material. Coating 40 may be applied to the outer surface 25 in any
desired manner. Although depicted with the coating 40 extending
along the entire reflecting surface 21, the coating may be
selectively applied so that it is only applied in the portion of
the reflecting surface at which most of the beam of light will
reflect.
[0033] Upon assembling optical coupling system 10, an index matched
medium 41 may be used to fill a first gap 16 (FIG. 1) between the
first optical component 11 and the first focal surface 30 of
coupling component 20 and a second gap 17 between the second
optical component 12 and the second focal surface 35 of the optical
component. It should be noted that FIG. 1 is not to scale for
purposes of illustration. The gaps 16, 17 may be any desired
distance, In one example, the gaps 16, 17 may be between 25 and 50
microns.
[0034] The refractive index of the medium 41 may closely match the
refractive indices of the first optical component 11, the second
optical component 12, and the coupling component 20. The medium 41
may be an index matched adhesive such as an epoxy that not only
transfers light between the first optical component 11, the second
optical component 12, and the coupling component 20 in an efficient
manner but also functions to secure the first optical component 11
and the second optical component 12 to the coupling component
20.
[0035] In an alternate embodiment, the first optical component 11
and the second optical component 12 may be secured to the coupling
component 20 using some structure or mechanism other than an
adhesive and the medium 41 may be an index matching gel, fluid or
other material that does not have adhesive qualities.
[0036] The index of refraction of the medium 41 may be any desired
value. In one example, the index of refraction of silica optical
fiber is approximately 1.48 and the index of refraction of the
polymer coupling component 20 is approximately 1.56. In such case,
the index of refraction of the medium 41 may be matched to
approximate the midpoint (i.e., approximately 1.52) between the
indices of refraction of the optical fibers and the coupling
component 20. In another example, the index of refraction of the
medium 41 may be set to be approximately equal to the index of
refraction of either the optical fibers or the coupling component
20. In still another example, the index of refraction of the medium
41 may be set at any value between the indices of refraction of the
optical fibers and the coupling component 20. Regardless of the
medium, the use of an index matched medium will generally result in
improved optical characteristics within the system 10.
[0037] The coupling component 20 provides the advantage of
redirecting and focusing an optical signal from the first optical
component 11 to the second optical component without transmitting
the signal through air and thus reduces the impact of changes in
temperature on the signal transmission. More specifically, as the
signal travels through the coupling component (i.e., from the first
foci 31 to the reflecting surface 20 and from the reflecting
surface to the second foci 36), it is subject to a constant index
of refraction along its entire path since it is always traveling
though the polymer material, Still further, the components other
than the coupling component 20 that form the optical path of system
10 (i.e., first optical component 11, second optical component 12
and medium 41), have very similar indices of refraction and thus
changes in temperature have a relatively small impact. By closely
matching the indices of refraction of the first optical component
11, the second optical component 12, the coupling component 20, and
the medium 41 and avoiding the transmission of the signal through
air, the impact of changes in the index of refraction due to
changes in temperature and resulting degradation in the optical
signal may be minimized.
[0038] By reducing the impact of temperature change with respect to
the refractive index, the beam of light or optical signal is
consistently focused on the target location. While this may be
desirable in most applications, it may be especially important when
one or both of the first optical component 11 and the second
optical component 12 are single mode optical fibers due to their
relatively small core diameter as compared to that of a multi-mode
optical fiber.
[0039] The shape of the coupling component 20 may also provide the
benefit of compensating to some extent for changes in the physical
structure of the coupling component due to expansion and
contraction with changes in temperature. More specifically, due to
the elliptical shape of the reflecting surface 21, the position of
the first focal point 31 and the second focal point 36 will
typically follow the position of the first optical component 11 and
the second optical component 12, respectively, as the coupling
component 20 changes size with changes in temperature.
[0040] While a preferred embodiment of the Present Disclosure is
shown and described, it is envisioned that those skilled in the art
may devise various modifications without departing from the spirit
and scope of the foregoing Description and the appended Claims.
* * * * *